Browsing by Author "Ravichandran, Vaithiyanathan"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Radius of starlikeness through subordination
    (Babes-Bolyai University, 2023-03-17) Sebastian, Asha; Ravichandran, Vaithiyanathan
    A normalized function f on the open unit disc is starlike (or convex) univalent if the associated function (Formula Presented) is a function with positive real part. The radius of starlikeness or convexity is usually obtained by using the estimates for functions with positive real part. Using subordination, we examine the radius of various starlikeness, in particular, radii of Janowski starlikeness and starlikeness of order β, for the function f when the function f is either convex or (Formula Presented) lies in the right-half plane. Radii of starlikeness associated with lemniscate of Bernoulli and exponential functions are also considered. © 2023,Studia Universitatis Babes-Bolyai Mathematica. All Rights Reserved.
  • No Thumbnail Available
    Item
    Starlikeness of Analytic Functions with Subordinate Ratios
    (Hindawi Limited, 2021-10-29) Ali, Rosihan M.; Ravichandran, Vaithiyanathan; Sharma, Kanika
    Let h be a nonvanishing analytic function in the open unit disc with h0=1. Consider the class consisting of normalized analytic functions f whose ratios fz/gz, gz/zpz, and pz are each subordinate to h for some analytic functions g and p. The radius of starlikeness of order α is obtained for this class when h is chosen to be either hz=1+z or hz=ez. Further, starlikeness radii are also obtained for each of these two classes, which include the radius of Janowski starlikeness, and the radius of parabolic starlikeness. © 2021 Rosihan M. Ali et al.